Note 15 - Commitments and Contingent Liabilities (Details Textual) - USD ($) $ in Millions	Aug. 26, 2014	Dec. 31, 2015	Dec. 31, 2014
Cargo Claim [Member]
Litigation Settlement, Amount	$ 5.9
Revenue Equipment [Member]
Purchase Commitment, Remaining Minimum Amount Committed		$ 145.6	$ 116.8
Letters of Credit Outstanding, Amount		$ 31.4	$ 34.3